The present invention relates to improved packages for forming and heat processing of food, particularly meat, and more specifically relates to apparatus and method by which dimensionally uniform processed meat products for high efficiency production and slicing are formed.
In the manufacture of sausage products, meat emulsion is prepared from comminuted meat together with fillers, seasonings, spices, etc. A tubular food casing, such as one containing nonedible cellulose, is loaded onto a stuffing horn of a filling machine and stuffed with the meat emulsion. In the case of small sausage products, like frankfurters, the filled casings are twisted, tied or clipped into suitable links at predetermined intervals and further processed. For larger sausage products, like bologna, salami, and the like, the meat emulsion is introduced into larger heavier walled casings or casings having fibrous reinforcements, and formed into chubs or lengthy individual sausage sticks or logs. The manufacture of other types of processed meats is carried out using the same general method.
In preparing larger diameter processed meat products, like bologna, an important consideration is the maintenance of accurate size control over the entire length of the log. It is important that the diameter of larger products be controlled very carefully so that meat packers are able to cut the log into slices of predetermined thickness and diameter for repackaging. The objective is to have a given number of slices weigh a precise predetermined amount for each package. That is to say, a given number of slices should weigh as close as practical to one pound or some other preselected weight. In addition, precise diameter control alone is important for vacuumized packages where the product must support the package and where varying diameters would be objectionable.
A further important consideration in the preparation of larger diameter processed meat products for repackaging concerns end portions. Processed logs which have rounded ends provide poor yields. Some degree of taper is usually present with round ends and further decreases yield. The end portions of a bologna log, for example, which are normally rounded and which may also be tapered can result in the loss of several inches of meat from each end of the sausage. Significantly undersized sliced product is not usable in most vacuumized display packages and must be reworked at significant cost.
In an effort to maximize yields of sliced product for repackaging, methods have been developed for eliminating rounded and undersized ends. One popular approach to this problem has been to prepare cylindrically shaped sausage products having flat ends by utilizing a variety of methods and apparatus. While such attempts have attained some degree of success, none has proven to be entirely satisfactory.
For example, U.S. Pat. No. 3,777,331 discloses apparatus for preparing sausage products with flat ends in which the meat mass is placed in a loading chamber having an undersized flat end plate at each end. The meat mass is compressed and extruded from the chamber and through a stuffing horn with one end plate at each end of the meat mass. A continuous length of tubular casing is filled with successive charges of the meat mass and end plates by transporting the free end of the casing with a conveyor onto the end of the horn from which the charges of meat mass are extruded. The casing end is clamped onto the stuffing horn and the conveyor retracted to its starting position whereupon the meat mass and end plates are extruded into the casing. Because the end plates and meat mass pass through the inside of the stuffing horn while the casing is clamped on the outside of the horn, the casing has the potential for a relatively loose fit over the encased meat product and end plates. This is undesirable because of possible "fat-out" and jelly pocket formation from an accumulation of water with fat and/or gelatin. Such products have an unappetizing appearance, and consequently, have poor customer acceptance. The casing of U.S. Pat. No. 3,777,331 must be stretched substantially to prevent fat out, etc., which can result in tapering of each product end as it approaches the end plates which are no larger, and slightly less than the diameter of the unstretched casing.
U.S. Pat. No. 3,650,774 discloses a casing structure with flat ends attached to thick end plates wherein the casing is clamped against the broad peripheral surface of the end plates by rings with a tapered bore. The casing is filled through a hole in one of the end plates. U.S. Pat. No. 3,650,774 also does not recognize the importance of casing stretch on product quality, nor the affect of casing stretch upon end taper when the end plates have the same periphery as the casing prior to stretching.
Other representative examples of devices for preparing dimensionally uniform encased sausage products with flat ends are disclosed by U.S. Pat. Nos. 4,551,884 and 4,466,465, both of which employ elaborate end plate assemblies having central openings which are costly to fabricate. These end plates, called "flattening annular disks" require a central opening because they are mounted onto the end of the stuffing horn. The hole, however, makes it necessary to gather the casing over the face of the disk and apply a clip to close the opening and avoid loss of meat emulsion during filling. However, this is not enough to prevent substantial loss of emulsion pressed through the hole during stuffing which fills the space between the disk and the gathered and clipped casing. Consequently, it is necessary to use a thin tubular film connecting the disks.
Large producers make 80% of processed meat in casing for slicing and repackaging. Each plant may make thousands of logs daily from each automatic stuffing machine which typically has one operator. The operator loads the logs into processing racks as well as tends to the stuffing machine, and replenishes casing and clips. For the sole operator to apply clamps to each end of each log, as required by the system shown in U.S. Pat. No. 3,777,331, for example, would substantially increase labor cost.
In addition, the bulk of each clamp would cause problems when the logs are loaded onto the horizontal processing racks. The logs are placed lengthwise upon parallel spaced rods that support the full length of the log. Clamps on each end of a log would prevent the log ends from lying smoothly on the rods and cause the product to be misshapen after processing. In addition, clamps added to the thick flat end plates double the number of extraneous parts that must be handled by the processors.
Accordingly, it would be highly desirable to have an improved system of packaging for encased meat products, including those which are suitable for filling with whole muscle and chunk style products to produce dimensionally uniform products, and which have flat ends to maximize yields of sliced products for repackaging. This would especially include large size fibrous cellulose casing packages for forming and heat processing of meat and other food that provide dimensional uniformity for high efficiency production and slicing.
A U.S. patent application Ser. No. 07/714,189, filed Jun. 12, 1991, in the name of the present inventor as a coinventor, describes a casing with reinforcements on its terminal ends that can coact with end plates to resist the axial forces generated when the casing is stuffed with food product and processed under pressure. This application, Ser. No. 07/714,189 is incorporated herein by reference, as are subsequent related applications, Ser. No. 08/001,287 and Ser. No. 07/982,027.